The present invention relates generally to vehicle restraints, and more particularly to a tire locating wheel restraint for securing a vehicle in a parking area.
The need for mechanisms to restrain parked vehicles against movement has long been known. Vehicle restraint is important in numerous industries which use trucks and other vehicles for the delivery of goods. Without proper restraints during loading and unloading, trucks can inadvertently move forward or backward from a dock creating the potential for harm to human life and property. This problem is readily apparent on docks employing a dock leveler, a device commonly used to adapt a dock of a fixed height to trucks of varying size or trailer bed height. With docklevelers, it is desirable to maintain a certain lip purchase to prevent the leveler from falling off the loading bed of the truck. This can be done by stabilizing the position of the truck with a chocking mechanism. In fact, the Federal Occupational Safety and Health Administration (OSHA) requires that wheel chocks be used in conjunction with dock levelers. However, through a letter opinion, OSHA has stated that it will permit the use of vehicle restraints in lieu of wheel chocks.
Vehicle restraints which block or otherwise place a barrier in front of one or more wheels of a vehicle are known in the art. Some such known restraints require manual placement of the wheel block, often referred to as a chock, adjacent the tire of the vehicle to be restrained. Other more sophisticated, restraints automatically position a locking assembly adjacent a tire of the vehicle either by translation of a barrier to a position adjacent the tire, or by forming a barrier adjacent the tire. Although many manual vehicle restraints are highly effective, in some instances, automatic vehicle restraints provide better restraint of vehicles than do manual chocks.
Unfortunately, tire size varies from vehicle to vehicle. Since automatic wheel restraints are limited by their geometry and operation, a given restraint may not make proper contact with wheels of every possible size; may, thus, not be able to effectively restrain a full range of vehicles; and, may therefore not be suitable for certain applications. More specifically, the geometry of prior art automatic vehicle restraints has, in some instances, resulted in a small gap existing between the locking assembly and the tire even after the tire has been xe2x80x9cchockedxe2x80x9d. Such a gap is disadvantageous because it affords the tire a running start at the locking assembly which could result in failure of the locking assembly (e.g., the tire jumping over the locking assembly or the locking assembly being collapsed or damaged).
The automotive industry provides particular challenges to vehicle restraints. In particular, the docks used at manufacturing facilities in the automotive industry are often higher than docks in other industries. Recently, trailers used to transport goods have become lower in the sense that the trailer beds reside closer to the ground. This combination of higher docks and lower trailer beds has resulted in the need for a means of compensating for this growing height differential-truck levelers. Truck levelers are mechanical devices that lift a trailer from the ground to achieve substantial leveling between a dock platform and the bed of the lifted trailer to facilitate loading and unloading of the trailer. Because the surface on which the truck is placed moves, chocking a vehicle on a truck leveler presents a new set of problems.
In accordance with an aspect of the invention, a tire locating wheel restraint is provided for use in restraining a vehicle having a tire in a parking area. The tire locating wheel restraint comprises a tire-locating mechanism in the form of a first trolley including a trigger that locates the tire of the vehicle. The first trolley is moveable between a first position wherein the trigger is displaced from the tire and a second position wherein the trigger contacts and thus locates the tire. The wheel restraint also comprises a tire-engaging mechanism in the form of a second trolley including a collapsible locking assembly having a distal portion for engaging the tire. The second trolley is moveable from a third position wherein the collapsible locking assembly is out of engagement with the tire to a fourth position wherein the distal portion of the collapsible locking assembly is in engagement with the tire. The first and second trolleys cooperate to erect the collapsible locking assembly adjacent the tire and then to move the erected locking assembly such that the distal portion of the collapsible locking assembly contacts the tire. The distance between the distal portion of the collapsible locking assembly and the trigger when the second trolley is in the fourth position and the first trolley is in the second position is dependent upon the size of the tire. That is, the first and second trolleys are moveable relative to each other. The wheel restraint is further provided with a drive mechanism for moving the first and second trolleys.
In accordance with another aspect of the invention, a tire locating wheel restraint is provided for use in restraining a vehicle having a tire in a parking area. The tire locating wheel restraint includes a first channel located in a first plane, and a second channel located in a second plane adjacent the first plane. The wheel restraint also includes a tire-locating mechanism in the form of a first trolley disposed for movement along the first channel. The first trolley includes a trigger positioned for sensing the tire of the vehicle. The wheel restraint is further provided with a tire-engaging mechanism in the form of a second trolley disposed for movement along the second channel and including a collapsible locking assembly having a distal portion for engaging the tire of the vehicle. The second trolley assembly includes a camming surface which cooperates with the first trolley to erect the collapsible locking assembly. The wheel restraint also includes a drive system for moving the first and second trolleys along the first and second channels, respectively.
In accordance with still another aspect of the invention, a method of restraining a vehicle having a tire in a parking area is provided. The method comprising the steps of moving a tire-locating mechanism in the form of a first trolley having a trigger relative to the vehicle until the trigger contacts the tire; moving a tire-engaging mechanism in the form of a second trolley having a collapsible locking assembly with a contacting surface relative to the first trolley to erect the collapsible locking assembly; and adjusting the distance between the trigger of the first trolley and the contacting surface of the collapsible locking assembly until the trigger and the contacting surface simultaneously abut the tire.
In accordance with still another aspect of the invention, a locking mechanism is provided for use with a sprocket having a plurality of teeth. The locking mechanism comprises first and second guide plates disposed in substantially parallel planes. The parallel planes are substantially perpendicular to a plane bisecting the sprocket into first and second halves. The locking mechanism also includes a brake plate disposed for sliding movement between the first and second guide plates. Additionally, the locking mechanism is provided with a tire-sensing mechanism in the form of a linear actuator coupled to the brake plate for reciprocating the brake plate between a first position wherein a distal edge of the brake plate is disposed between at least two teeth of the sprocket to thereby substantially lock the sprocket against rotation and a second position wherein the distal edge of the brake plate is separated from the sprocket to permit rotation thereof.
In accordance with still another aspect of the invention, a tire locating wheel restraint is provided for use in restraining a vehicle having a tire in a parking area. The tire locating wheel restraint comprises a tire-locating mechanism that locates the tire of the vehicle. The tire-locating mechanism is moveable between a first position, displaced from the tire and a second position, locating the tire. The wheel restraint also comprises a tire-engaging mechanism including a collapsible locking assembly having a distal portion for engaging the tire. The tire-engaging mechanism is moveable from a third position wherein the collapsible locking assembly is out of engagement with the tire to a fourth position wherein the distal portion of the collapsible locking assembly is in engagement with the tire. The tire-locating mechanism and tire-engaging mechanism cooperate to erect the collapsible locking assembly and then to move the erected locking assembly such that the distal portion of the collapsible locking assembly contacts the tire. The distance between the distal portion of the collapsible locking assembly and the tire-locating mechanism when the tire-engaging mechanism is in the fourth position and the tire-locating mechanism is in the second position is dependent upon the size of the tire. That is, the tire-locating mechanism and the tire-engaging mechanism are moveable relative to each other. The wheel restraint is further provided with a drive mechanism for moving the tire-locating mechanism and the tire-engaging mechanism.
Other features and advantages are inherent in the apparatus claimed and disclosed or will become apparent to those skilled in the art from the following detailed description and its accompanying drawings.